The present invention relates to an image forming apparatus, and more particularly, to an image forming apparatus having an auxiliary reflecting mirror placed around the flanks of a sheet of paper bearing an image, so as to effectively prevent a phenomenon in which the data corresponding to the flanks of the image are not precisely input.
Generally, in an image forming apparatus such as a color image scanner, color printer, digital color copier or the like, the light emitted from a light source such as a lamp is reflected from an image on a sheet of paper and the image is, in turn, formed on a photoelectric converting device by lenses. As the photoelectric converting device, for instance, a charge-coupled device (CCD) string is widely used. Each CCD outputs a signal corresponding to image information formed thereon. In accordance with image output devices, the signal is converted into digital form for transmission to an output device such as a printer or is processed as binary code for facsimile telegraphy.
In a conventional image forming apparatus, referring to FIG. 1, a fixed reflecting mirror 2 for reflecting light onto a sheet (not shown) bearing an image is located under lamp 1 along the whole length of lamp 1 so that the light is converged on the sheet. As shown in FIG. 5, however, the voltage output according to the light amount detected by a CCD sensor is lower around the center of the image-bearing sheet than on the flanks thereof. Due to the difference of light intensity between the center and the flanks, when an image is output, the image on the flanks of the sheet of paper becomes less clear than that on the center thereof.